Fix for CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

[asadeddin]

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It issued this PR to fix a vulnerability for you to review.

See the issue and fix in Corgea.

Explanation of the issue

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Cross-site scripting (XSS) vulnerabilities occur when:

Untrusted data enters a web application, typically from a web request.
The web application dynamically generates a web page that contains this untrusted data.
During page generation, the application does not prevent the data from containing content that is executable by a web browser, such as JavaScript, HTML tags, HTML attributes, mouse events, Flash, ActiveX, etc.
A victim visits the generated web page through a web browser, which contains malicious script that was injected using the untrusted data.
Since the script comes from a web page that was sent by the web server, the victim's web browser executes the malicious script in the context of the web server's domain.
This effectively violates the intention of the web browser's same-origin policy, which states that scripts in one domain should not be able to access resources or run code in a different domain.

Explanation of the fix

The security fix addresses a Cross-site Scripting (XSS) vulnerability by correctly neutralizing user-controllable input before it is placed in output that is used as a web page. This is achieved by using a safer method to format HTML strings in Python.

• The vulnerability was a Cross-site Scripting (XSS) issue, where untrusted data was not being properly neutralized before being used in a web page. This could allow an attacker to inject malicious scripts.
• The fix involves changing the way user-controllable input is formatted into an HTML string. Instead of directly embedding the user input into the string (which could contain malicious scripts), the input is now passed as arguments to the 'format_html' function.
• This function safely formats the input into the HTML string, ensuring that any potentially harmful scripts are neutralized.
• The change is made in the 'first_member' method of the 'OrganizationAdmin' class in the 'posthog/admin.py' file.
• This fix effectively mitigates the risk of XSS attacks by ensuring that user-controllable input is properly sanitized before being used in a web page.